A novel two-step method was designed for NH3 removal at low temperature (150-200 degrees C) in this work. In step 1, the selective catalytic oxidation of NH3 to NOx occurred on the SCO catalyst to make the outlet [NH3]/[NOx] approximate to 1. In step 2, the selective catalytic reduction of formed NOx by unreacted NH3 occurred on the SCR catalyst, so as to improve the NH3 removal efficiency and N-2 selectivity of the whole two-step reaction process. For the step 1 catalyst, a series of TiO2 supported transition metal oxides catalysts were prepared and tested to select the suitable one. The two-step method showed superior catalytic performance with the NH3 removal efficiency higher than 95% as well as the N-2 selectivity higher than 85% in 170-180 degrees C by using 7.5CoO(x)-7.5CuO(x)/TiO2 as the step 1 catalyst and NiMn2O4 as the step 2 catalyst. The analysis of the N2O formation indicated that the N2O formation of the two-step method mainly consisted of the N2O formed in step 1 and step 2 catalysts. The N-2 selectivity of the two-step method at 150-170 degrees C can be improved by the following ways: reducing the N2O formed by NH3 oxidation on the step 2 catalyst, increasing the NOx formed on the step 1 catalyst to inhibit the oxidation of NH3 on the step 2 catalyst, and further reducing the N2O formation on the step 1 catalyst.